NMEA RMC datagram format
The NMEA RMC datagram transfers the time, date, position, course and speed data from a global navigation satellite system (GNSS) receiver.
Format
$--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,z.z,ddmmyy,r.r,a,a*hh
Description
1 $—: Talker identifier
2 RMC: Datagram identifier
3 hhmmss.ss: Coordinated Universal Time (UTC) of the current position
4 A: Status
•  A = The data are valid.
•  V = The data are not valid.
5 llll.ll,a: Latitude, North/South (Degrees, minutes and hundredths)
•  N = North
•  S = South
6 yyyyy.yy,a: Longitude, East/West (degrees, minutes and hundredths)
•  W = West
•  E = East
7 x.x: Speed over ground (knots)
8 z.z: Course over ground (degrees  (True))
9 ddmmyy: Date
10 r.r,a: Magnetic variation, East/West (degrees)
•  E = East
•  W = West
11 a: Mode indicator
12 *hh: Checksum